> >>common in today's circuits. Also, 0.01 uF caps are less expensive and > take > >>up less space (0805 vs. 1206). > > Huh? Why would you use a 1206 0.1uf for anything unless you needed 50WVDC > or more rating? > > Everything I have read on bypassing for digital says to use 0603 or > smaller parts since they have lower inductance, and at the moment 0603 is > the most cost effective. On a current design I have 0603 0.1uf, 0.01uf and > smaller, 0805 1uf and 1210 10uf ceramic caps, besides the larger > tantalums.
The operative phrase above is "at the moment". Well, at the moment I did my cost/size comparison, 0.01 uF 0805 was cheaper than 0.1 uF 1206 and 0805. I suspect this is still the case, at least it was last time I bought a reel of caps. I don't use 0603 parts yet, due to lack of need for them. Maybe soon though. You are correct about smaller case size leading to lower inductance. I also try to minimize the number of distinct parts used in our products, to keep inventory manageable and get as much economy of scale across our product line as we can in a small operation. When I say small, I mean we don't produce a blue-purple-zillion units a year like the chip companies expect us all to do. Most of us are not in the cellphone and video game console business! Whatever happened to the effort to start a Protel User's website with downloadable footprints and such? I remember some enthusiatic discussion about this maybe a year or two ago, but nothing since. And whatever happened to Adbul (Abd ul-Rahman Lomax)? He seems to have dropped of this list. Or maybe he is a DXP user now? Forget Carmen Santiago, Where in the world is Abd ul-Rahman Lomax? Best regards, Ivan Baggett Bagotronix Inc. website: www.bagotronix.com ----- Original Message ----- From: <[EMAIL PROTECTED]> To: "Protel EDA Forum" <[EMAIL PROTECTED]> Sent: Tuesday, June 03, 2003 6:45 PM Subject: Re: [PEDA] six or eight-layer (or more?) stackups - Capacitance * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[EMAIL PROTECTED] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
